Not looking forward to pedaling your bike on your trainer in your living room all winter? Shift your focus to indoor competition. Both veteran and budding triathletes can take advantage of the growing number of climate-controlled events in the Twin Cities.

Indoor triathlon season starts Sunday, when the Minneapolis YWCA hosts its first of three competitions at its Midtown location and Life Time Fitness kicks off the season with one of several local events (16 in 2011) at its St. Louis Park location.

Both gyms say the events are becoming more popular: Life Time will host 80 indoor triathlon events nationwide in 2011, up from 30 in 2008. The Y has turned its event into a series to offer more registration spots and to encourage improvement over the course of the series.

"Having events on the horizon is a great motivator," said Nicole Cueno, the Y's endurance sports coordinator. "This may be even more important for keeping us going in the Minnesota winters than it is during our gorgeous summers. For those who do not love the open water of summer tris, indoor tris add some added comfort by using the pool."

The Y events closely resemble an outdoor triathlon: Participants choose a mini-sprint or sprint option, swim 400 or 600 yards, bike 8 or 10 miles on a stationary bike, and run 1 or 2 miles on an indoor track.

The Life Time events take a slightly different twist: Competitors tally points based on how far they can run, bike and swim in an allotted number of minutes (10 minutes of swimming, 30 minutes of stationary biking and 20 minutes on the treadmill).

"Endurance athletes need to give their body a break from extreme training, but still maintain a strong base level of fitness," said Debbie Hale, event manager with Life Time Endurance. "As workouts are forced to shift indoors, it is more important than ever to vary your workouts to keep exercise fresh."

Try something new, she suggests: a Zumba or Pilates class, or hone your technique at a Masters swim practice.

Find out what your gym offers for endurance sports lovers. (Life Time has groups for cycling and running, and the Y will have monthly clinics focusing on endurance sports.) Bring your bike and trainer to a two- or five-hour spin class at the Y, for example.

Sign up for more than one: Kris Ferkingstad, who placed third in the Y's most improved category at the outdoor triathlon, credits much of her success to doing all three indoor triathlons last year.

Find more Twin Cities indoor events, including Tri-U-Mah at the University of Minnesota, at www.trifind.com/mn.

Sheila Mulrooney Eldred is a Twin Cities freelance writer.